Provide option to suppress mirrors metadata

lib/src/compiler/code_generator.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:collection' show HashMap, HashSet;
 import 'dart:math' show min, max;
 
 import 'package:analyzer/analyzer.dart' hide ConstantEvaluator;
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart' show Token, TokenType;
@@ skipping 1130 matching lines @@
         }
       }
     }
     if (lazyStatics.isNotEmpty) {
       body.add(_emitLazyFields(classElem, lazyStatics));
     }
   }
 
   void _emitClassMetadata(List<Annotation> metadata, JS.Expression className,
       List<JS.Statement> body) {
-    // TODO(vsm): Make this optional per #268.
     // Metadata
-    if (metadata.isNotEmpty) {
+    if (options.preserveAnnotations && metadata.isNotEmpty) {
       body.add(js.statement('#[dart.metadata] = () => #;', [
         className,
         new JS.ArrayInitializer(
             new List<JS.Expression>.from(metadata.map(_instantiateAnnotation)))
       ]));
     }
   }
 
   /// If a concrete class implements one of our extensions, we might need to
   /// add forwarders.
@@ skipping 1051 matching lines @@
           : (p as DefaultFormalParameter).parameter.metadata;
 
   JS.ArrayInitializer _emitTypeNames(List<DartType> types,
       [List<FormalParameter> parameters]) {
     var result = <JS.Expression>[];
     for (int i = 0; i < types.length; ++i) {
       var metadata =
           parameters != null ? _parameterMetadata(parameters[i]) : [];
       var typeName = _emitType(types[i]);
       var value = typeName;
-      // TODO(vsm): Make this optional per #268.
-      if (metadata.isNotEmpty) {
+      if (options.preserveAnnotations && metadata.isNotEmpty) {
         metadata = metadata.map(_instantiateAnnotation).toList();
         value = new JS.ArrayInitializer([typeName]..addAll(metadata));
       }
       result.add(value);
     }
     return new JS.ArrayInitializer(result);
   }
 
   JS.ObjectInitializer _emitTypeProperties(Map<String, DartType> types) {
     var properties = <JS.Property>[];
@@ skipping 2260 matching lines @@
 }
 
 bool isLibraryPrefix(Expression node) =>
     node is SimpleIdentifier && node.staticElement is PrefixElement;
 
 LibraryElement _getLibrary(AnalysisContext c, String uri) =>
     c.computeLibraryElement(c.sourceFactory.forUri(uri));
 
 bool _isDartRuntime(LibraryElement l) =>
     l.isInSdk && l.source.uri.toString() == 'dart:_runtime';